This invention relates to a tamperproof closure system for molded plastic containers with sterile solutions. More particularly, the invention relates to a break-away closure for a sterile solution container wherein an outer cap, which will afford a break-away feature, can be machine assembled on the bottle neck without threads prematurely engaging, yet can form a sterile environment seal for the container neck area.
Previously, cap opening devices of the type concerned with in this invention have been sealed to a bottle flange by means of interference fitment gaskets, O-type sealing rings, hot melt procedures, or with tape. These systems do not provide consistently a sterile environment at or around the bottle opening until first use. The use of spin or ultrasonic welding techniques offers a sterile environment between a threaded outer cap and the threaded bottle neck. However, threaded engagement of the bottle and the cap must be avoided and a means must be provided to retain the cap when a portion of the container is severed. In U.S. Pat. No. 3,245,858, the spin welding of a plastic closure is illustrated. In U.S. Pat. Nos. 4,176,755 and 4,378,891 a pre-engagement of the threads of the outer cap with the container is illustrated, or a jacking ring is employed in conjunction with the inner closure.
The prior art does not provide a tamperproof closure system for threaded molded plastic containers wherein the outer cap can be machine assembled and sealed onto the threaded container neck without premature engagement of the threads between the cap and the container, yet will permit a severing of a portion of the container and captively hold it for reclosure purposes after severing.
It is an advantage of the present tamperproof closure system to provide a sterile closure feature with a severing type cap which can be machine assembled onto a container. Other advantages are a closure cap which prevents the accidental stressing of the container frangible section until the tear-away portion is removed; a closure cap which will not prematurely engage the threads on the container, yet will afford a captive function after a portion of the container is severed; a tamperproof and severing closure system which obviates the necessity for additional seals and sealing techniques; and a tamperproof closure system which can be molded from molding equipment without substantial alteration and can be machine assembled by standard assembly machines.